Various alkali metal halide aqueous solutions e.g., NaCl brine, contain Mg.sup.++ ions and/or Ca.sup.++ ions which are considered detrimental if the aqueous solution is intended for use in certain applications, such as in an electrolytic process. These are commercial incentives to substantially removing the Mg.sup.++ and/or Ca.sup.++.
It is known that hydrous zirconium oxide and other zirconium compounds, such as zirconium phosphates, are useful as inorganic ion exchangers.